This site, edited by Ian Scott of Tyndale Seminary, contains online editions of many Old Testament Pseudepigrapha in various ancient and medieval languages, though the basis for most is Greek, with Latin also well represented. The Introductions to each text are original and helpful, including a description of the manuscript evidence across multiple versions, and an annotated bibliography of print editions designating manuscripts used, which can also be browsed by author or keyword and searched. The currently available electronic texts are often a transcription of an out-of-copyright edition, and sometimes include evidence from multiple manuscripts; eclectic texts taking into account extant versions in Coptic, Syriac, Armenian, Ethiopic, and other languages are planned.
While the Online Critical Pseudepigrapha is still very much a work in progress, it is laudable for its efforts to make widely available the electronic text of these important documents, and thus multiplying possibilities for research. The full texts of widely cited works such as the Lives of Adam and Eve and the Testament of Abraham, which are not yet in Perseus or other open access digital library, can now be employed in DH research, for example corpus analysis with the statistics program R; copyright information varies by text, and a full statement is given here: http://ocp.tyndale.ca/copyright-and-permissions